Electrolysis apparatus for collecting nitrogen compound using ferric-ethylenediamine tetraacetic acid

Abstract

The present invention relates to an electrolysis apparatus for collecting a nitrogen compound using ferric-ethylenediaminetetraacetic acid (Fe-EDTA), and more particularly, to an electrolysis apparatus for collecting a nitrogen compound in exhaust gas by supplying electric energy to cause a redox reaction of Fe-EDTA.

What is claimed is: 
     
       1. An electrolysis apparatus for collecting a nitrogen compound, comprising:
 (a) a reactor body comprising a compound of divalent metal ion and chelating agent therein; 
 (b) an anode and a cathode; 
 (c) a collection tube for collecting the nitrogen compound, comprising the anode therein; 
 (d) a gas inlet for supplying raw material gas containing the nitrogen compound to the reactor body; 
 (e) an outlet for discharging gas which has been collected inside the reactor and from which the nitrogen compound is removed; and 
 (f) a pretreatment vessel arranged to receive a gas containing nitrogen oxides and to contact said gas containing nitrogen oxides with water in the pretreatment vessel to yield (i) nitric acid (HNO 3 ) and (ii) gas containing the nitrogen compound as said raw material gas. 
 
     
     
       2. The electrolysis apparatus for collecting a nitrogen compound of  claim 1 , further comprising:
 (g) the pretreatment vessel being arranged to receive a gas containing NO 2  and the nitrogen compound, for reacting NO 2  and water to yield NO 2 -removed raw material gas containing the nitrogen compound and separating nitric acid wherein the nitrogen compound comprises NO; 
 (h) a NO collection vessel arranged to receive the NO 2 -removed raw material gas from the pretreatment vessel, and to contact the NO 2 -removed raw material gas with the compound of divalent metal ion and chelating agent to selectively adsorb NO by the compound of divalent metal ion and chelating agent, and thereby remove NO from the NO 2 -removed raw material gas to yield a treated gas that is discharged from the NO collection vessel; and 
 (i) a NO separation and regeneration vessel, arranged to receive the compound of divalent metal ion and chelating agent with selectively adsorbed NO, for electrochemical reaction therein to separate the NO from the compound of divalent metal ion and chelating agent, and regenerate the compound of divalent metal ion and chelating agent, so that the separated NO is discharged from the NO separation and regeneration vessel and supplied to the reactor body as said raw material gas. 
 
     
     
       3. The electrolysis apparatus for collecting a nitrogen compound of  claim 1 , wherein the divalent metal ion is iron, aluminum, magnesium, potassium, copper, zinc, nickel, cobalt, manganese, lead, silver, gold or chromium. 
     
     
       4. The electrolysis apparatus for collecting a nitrogen compound of  claim 1 , wherein the chelating agent is ethylenediamine tetraacetic acid (EDTA). 
     
     
       5. The electrolysis apparatus for collecting a nitrogen compound of  claim 1 , wherein the compound of divalent metal ion and chelating agent is Fe(II)EDTA. 
     
     
       6. The electrolysis apparatus for collecting a nitrogen compound of  claim 1 , wherein the reactor has an upper reactor cover mounted on the upper end, capable of injecting the compound of divalent metal ion and chelating agent. 
     
     
       7. The electrolysis apparatus for collecting a nitrogen compound of  claim 1 , the compound of divalent metal ion and chelating agent has a concentration of 10 mM-0.5 M. 
     
     
       8. The electrolysis apparatus for collecting a nitrogen compound of  claim 1 , wherein the anode is composed of a mixture of one or more conductive materials selected from the group consisting of graphite, platinum, titanium, nickel and gold, and one or more catalysts selected from the group consisting of platinum, ruthenium, osmium, palladium, iridium, carbon and transition metals. 
     
     
       9. The electrolysis apparatus for collecting a nitrogen compound of  claim 1 , wherein the cathode is composed of a mixture of one or more conductive materials selected from the group consisting of graphite, platinum, titanium, nickel, gold, iron, copper and aluminum, and one or more catalysts selected from the group consisting of platinum, ruthenium, osmium, palladium, iridium, carbon and transition metals. 
     
     
       10. The electrolysis apparatus for collecting a nitrogen compound of  claim 1 , wherein a porous plate is provided on a lower portion of the collection tube. 
     
     
       11. The electrolysis apparatus for collecting a nitrogen compound of  claim 1 , wherein the nitrogen compound is nitrogen oxide (NO x ). 
     
     
       12. The electrolysis apparatus for collecting a nitrogen compound of  claim 11 , wherein the nitrogen oxide is nitrogen monoxide (NO). 
     
     
       13. A method of collecting a nitrogen compound using the electrolysis apparatus of  claim 1 , comprising:
 (i) adsorbing the nitrogen compound to the compound of divalent metal ion and chelating agent by supplying raw material gas comprising a nitrogen compound to a reactor containing a compound of divalent metal ion and chelating agent; 
 (ii) collecting discharged nitrogen compound by supplying electricity to an anode and a cathode, oxidizing the nitrogen compound-adsorbed compound of divalent metal ion and chelating agent to a compound of trivalent metal ion and chelating agent through an oxidation reaction in the anode and discharging the nitrogen compound; 
 (iii) recovering collected nitrogen compound; and (iv) reducing oxidized compound of trivalent metal ion and chelating agent to the compound of divalent metal ion and chelating agent by electrons produced in the cathode. 
 
     
     
       14. The method of collecting a nitrogen compound of  claim 13 , wherein the nitrogen compound is nitrogen oxide (NO x ). 
     
     
       15. The method of collecting a nitrogen compound of  claim 14 , wherein the nitrogen oxide is nitrogen monoxide (NO). 
     
     
       16. The method of collecting a nitrogen compound of  claim 13 , further comprising a step of (v) preparing nitric acid (HNO 3 ) using collected nitrogen compound. 
     
     
       17. The method of collecting a nitrogen compound of  claim 13 , further comprising, prior to the step (i)
 a NO 2  removal step of reacting NO 2  in the raw material gas and water to obtain nitric acid (H NO 3 ) by, spraying water to the raw material gas in the pretreatment vessel; and 
 wherein the adsorbing step (i) comprises a NO collection step of reacting the NO 2 -removed raw material gas with the compound of divalent metal ion and chelating agent and separating NO.